back to index

Logic families and chips
      families
      switching levels
      LittleLogic: single (dual, triple) gates
      standard Vcc levels:
                  bus switches
                  high-speed memory interfaces
                  high-speed backplane
            selection, as of 2000
            GTL, GTL-P
      bus switches
            CBT - general purpose 5v
            CBT-C - improved 5v
            CBTLV - 3.3v, 2.5v
            CB3Q - 3.3v, 2.5v, to 500MHz
            CB3T - 5/3.3v bus translator
            naming
      analog switches
      I2C IO expanders
      I2C level converter
            I2C multiplexers

Logic families and chips

Texas Instruments naming:
SN74LVCH162244ADGGR
SN:mfg|74:temp-range|LVC:family|H:features|16:bit-width|2:options|244:function|A:revision|DGG:packaging|R:reel(T:tape)

...1G (2G,3G) - single(2,3)-gate package

http://www.siongboon.com/projects/datasheet/logic%20gates%20&%20family%20selection%20guide%20%28ti%29.pdf ; temp: 74: commercial 54: military features: A,B,C: configurable Vcc D: level-shifting diode H: bus hold K: undershoot clamp R: damping resistors on inputs-outputs S: Schottky clamping diodes Z: power-up tristate options: 2: damping resistors on outputs 3: level shifter 4: level shifter 25: 25-ohm driver width: 1G,2G,3G: single/dual/triple gates 8: octal IEEE 1149 16: Widebus (16,18,20) 18: Widebus IEEE 1149.1 (18) 32: Widebus+ (32,36) IEEE1149==JTAG features: bus hold: holds last known input state, no floating inputs issues - high-impedance resistor feedback into input, maintains state at high-Z on input damping resistors: in series with outputs (and/or inputs), damping reflectios, improving termination - I/O pins: LVCHR16245, out-only: LVC162244 level 1 isolation - partial power down: IOFF circuits, prevents damage at hot insertion - no sourcing current through parasitic diodes - allows partial powerdown of circuitry level 2 isolation - hot insertion: + power-up tristate - valid outputs at power-up, valid Z-state at power-down - outputs at high-Z at below-threshold (supply trip point) Vcc level 3 isolation - live insertion: + precharges capacitances, prevents glitching of data - Bias Vcc input, shorter-than-IO Vcc pin, longer-than-IO GND and BiasVCC for staggered mating - bias vcc mates first, precharges gates at chip inputs so they don't take full charge pulse on mating to IO bus mixed-voltage-tolerant, active level-shifting - can have two Vcc feeds

families

5V high-perf: ABT, ABT-C
5V low-perf: AHC == VHC
3.3V high-perf: CBT-LV; ALVT; ALVC == VCX
3.3V med-perf: LVT; LVC == LCX
3.3V low-perf: LV-A == LV == LVQ|LVX (these two differ)
2.5V high-perf: AVC
1.8V high-perf: AUC

ECL: Emitter-Coupled Logic, fastest, transistors in unsaturated mode, hot and power-hungry
  Unsaturated transistors have a faster switching time because of the absence of minority charge storage.



switching levels

                                            V_oL V_iL   Vthr   V_iH V_oH
5V   TTL    HCT bipol AHCT HCT ABT ACT      0.4  0.8    1.5    2.0  2.4
5V   CMOS   HC AHC AC LV-A                  0.5  1.5    2.5    3.5  4.44
3.3V LVTTL  LVT ALVT LVC ALVC AUP LV-A      0.4  0.8    1.5    2.0  2.4
2.5V CMOS   AUC AUP AVC ALVC LVC ALVT       0.2  0.7    1.2    1.7  2.3
1.8V CMOS   AUC AUP AVC ALVC LVC            0.45 0.7    0.9    1.17 1.2

LVCMOS
LVPECL


GTL 1.2v    GTL                             0.4  0.75   0.8    0.85 1.2      GTL,GTL+,GTLP - open-drain, 25ohm pullup to Vcc; input diff, reference to R-2R divider to Vthr
GTL 1.5v    GTL+, GTLP                      0.55 0.95   1.00   1.05 1.5      GTLP slew rate optimized for distributed loads


LittleLogic: single (dual, triple) gates

      Vcc         prop.delay   output  Vtolerant
       from optim  to     ns      mA     V
  AUC   0.8  1.8  2.7    2.0      8     3.6   Ioff   1.8v, full 8mA drive at 1.8v
  AUP   0.8  3.3  3.6    5.4      4     3.6   Ioff   lowest-power  input hysteresis (250mV@3.3v) for glitchfree slow input transitions
! LVC   1.65 3.3  5.5    3.5     24     5.5   Ioff
! AHC   2.0  5.0  5.5    5.0      8     5.5
  CBT   4.5  5.0  5.5    0.25 (switch)  5.5
  CBTD  4.5  5.0  5.5    0.25 (switch)  5.5
  CBTLV 2.3  3.3  3.6    0.25 (switch)  3.6   Ioff

output at Vopt; e.g. 4mA@3.3v, but 1.9mA@1.8v, 1.1mA@1.2v
Ioff=no current sourcing through parasitic diodes

standard Vcc levels:

b=bipolar, bi=biCMOS, unspecified=CMOS
Istatic in µA
drive in mA, - source, + sink

         0.8 1.2 1.8 2.5 3.3 5.0    Vinmax LevIn  LevOut  Tpd  drive Istatic Ioff ESD noise
     AUC  +   +   ++  +  (i)        3.6   LVCMOS  LVCMOS  2.0    8        10   +    +   low        low-voltage, optimized for 1.8V, works from 0.8V
     ULP // == AUC
     AUP  +   +   +   +   ++        3.6   LVCMOS  LVCMOS         4         1   +    +              very low power consumption
     ALVC         +   +   ++        Vcc   (LV)TTL LVCMOS  3.0   24        20   +    +   low        fast, prop delay below 3ns at 3.3v, -6/+12mA drive at 2.5v, low noise
     VCX // == ALVC
     ALVCF            +   ++        Vcc   (LV)TTL LVCMOS  3.5   12        40   +    +   low        fast memory interface for PC133, -6/+12mA drive at 2.5v, low noise
     AVC          +   ++  +         3.6   LVCMOS  LVCMOS  2.0    8        20  10uA                 sub-2 nsec at 2.5v, DOC (Dynamic Output Control) eliminates ringing/overshot
     AVCH
 !   LVC(Z)       +   +   ++ (i)    5.5   (LV)TTL LVCMOS  4.0   24        10  10uA  +              reliable, 3.3v for 5v interfacing, LVCZ for hot insertion
     LCX // == LVC
     LPT // == LVC
     LV-A             +   ++  +      5    LVCMOS  LVTTL  14.0    8        20   5uA? +   low        expanded voltage operation range
     LV  // == LV-A? 74LV04 says it works down to 1.0V Vcc, input tolerant to Vcc
     LVX // == LV-A? MC74LVC04 says inputs tolerant to 7v, recommend 5.5max, Vcc max 7v, recommended 3.6v
     LVQ // == LV-A
  Bi LVT                  ++ (i)     5    (LV)TTL LVTTL   3.5  -32+64    190 100uA      low        high drive, -32/+64mA at 3.3v, Tpd below 3.5ns, hot insertion, tristate below 1.5V
  Bi ALVT             +   ++ (i)     5    (LV)TTL LVTTL   3.5   -8+24   4500 100uA                 high drive, -32/+64mA at 3.3v, -8/+24mA at 2.5v, hot insertion, tristate below 1.2V, tristate at output forced above Vcc
  b  ALB                  +        V+0.5  custom  custom  2.0   25       800                       max propagation delay 2.2ns
 .   AC           ?   ?   +   ++   V+0.5  CMOS    CMOS    6.5   24        40                       1.5V to 5.5V, noise immunity at 30% Vcc
 !   HC               +   +   ++    Vcc   CMOS    CMOS   21.0    7.8      80                       reliable, low to mid speed
 !   AHC              ?   +   ++    5.5   CMOS    CMOS    7.5    8        40                       migration from HC, low noise
     ACT                      +     Vcc   TTL     CMOS    8.0   24        40                       like AC in TTL, reliable, low-power, 24mA at 5v
 !   AHCT                     +     5.5   TTL     CMOS    7.7    8        40
 !   HCT                      +     Vcc   TTL     CMOS   30.0    6        80                       like HC in TTL
     FCT                      +     Vcc   TTL     TTL     5.3  -15+64     80
     VHC              +   ++  ++    5.5                   5.5?                                     twice-fast than HC, 5ns typ prop. delay, 0.8Vmax V_olp == low noise, max. 170MHz@5v/125MHz@3V (Cl=15pF)
     VHCT                     +     5.5   TTL     TTL     5.5?                 ?                   like VHC in TTL
     XC7SH == 1-device VHC
     XC7SET == 1-device VHCT
     VHC9 == Schmitt input VHC
     VHCV == Schmitt input VHC, twice output current                                       VHCT,VHCV,LCX,VCX - no out-Vcc diode; VHC,VHCT,VHC9,VHCV,LCX,VCX - no in-Vcc diode
     VCX                                                               ?
 .b  ALS                      +      5    TTL     TTL    10.0  -15+24  58000
  b  AS                       +      5    TTL     TTL     7.5  -15+64 143000                       high-speed, high-drive TTL
 .b  F                        +      5    TTL     TTL     6.0   -3+24 120000                       high-speed general purpose TTL
 .b  LS                       +      5    TTL     TTL    12.0  -15+24  95000                       old classics
  b  S                        +      5    TTL     TTL     9.0  -15+64 180000
  b  TTL                      +      5    TTL     TTL    22.0 -0.4+16  22000
  Bi ABT                      +      5    (LV)TTL TTL     3.5  -32+64    250 100uA                 reduced transmission-line effect, fast, high-drive, tristate below 2.1V
  Bi ABTE                     +      5    ETL     TTL     5.2   12        48                       backplane driver, wider noise margin, compatible with TTL, live insertion, bus hold
  Bi BCT                      +      5    (LV)TTL TTL     6.6   -3+24  90000                       high-speed, 64mA drive, very low power when disabled
  Bi FB                       +      5                          100?           +                   backplane driver
 !   4000 (CD4K)         (+)  +>>>  Vcc   CMOS    CMOS varies -0.2+0.5     5                       Vcc to 18V, slow
     ECL
     BPSR
     EP
     HEF
     NL
     NLU
     HS
     HST
     ULP
     ULP-A
     VHS
bus switches
     CBT(-C)              +  (i)    5.5   TTL     TTL    (0.25) n/a        3                       bus switch (bidirectional FET)
     CBTLV(-C)            +         3.6   LVCMOS  LVCMOS (0.25) n/a       10                       bus switch (bidirectional FET)
     CB3Q                                                (0.25) n/a      700
     CB3T                                                (0.25) n/a       40
     PI3B // == CBTLV
     CBTD == CBT with integrated diode; bidir between 5vTTL and 3.3vLVTTL, unidir from 5vCMOS -> 3.3vLVTTL
high-speed memory interfaces
     HSTL                 +         3.3   HSTL    LVTTL   5.0   24     50000                       HSTL-to-LVTTL memory address latches
     SSTL             +   ++        3.3   SSTL_3  SSTL_3  3.7   20     90000                       high-speed memory interface for PC133, to 200 MHz
     SSTV             +  (i)        3.3   SSTL_2  SSTL_2  2.8   16     56000                       high-speed memory interface for PC1600/2100 == DDR200/266
     SSTVF            +  (i)        3.3   SSTL_2  SSTL_2  2.6   16     56000                       high-speed memory interface for PC2700/3200 == DDR333/400
     SSTU         +  (i)            2.5   SSTL_1  SSTL_1  2.5    8     50000                       high-speed memory interface for PC2-3200/4300 == DDR2 400/500
high-speed backplane
     GTL                  +  (i)     5    diff    oc      6.5  +50     80000 100uA                 high-speed backplane, to 160MHz, live insertion, GTL=point-to-point
     GTLP                 +  (i)     5    diff    oc      7.7  +100    80000 100uA                 high-speed backplane, to 160MHz, live insertion, GLTP=multipoint backplane
  Bi VME                  +  (i)     5    (LV)TTL (LV)TTL 14.5   24    30000   +                   high-speed backplane

overvoltage-tolerant IO:  LV, LVC, ALVC, LVT, ALVT, AVC, GTL, GTLP
Ioff:                     100uA: ABT, LVT, ALVT, GTL, GTLP; 10uA: LVC, AVC; 5uA: LV
power-up tristate:        ABT, LVT, ALVT, LVC, GTLP
auto-tristate on output overvoltage:   ALVT
DOC, transient low impedance on change: AVC
JTAG:                     ACT, BCT, ABT, LVT


selection, as of 2000

                          5V             3.3V
high speed, high drive: ABT (F)       LVT (ALVC)
high speed, low noise:  ABT (F)       ALVC (LVT LVC ALB)
high speed, low power:  ABT (AC/ACT)  ALVC (LVT LVC ALB)

high drive, high speed: ABT (F)       LVT (ALVC)
high drive, low noise:  ABT (F)       LVT
high drive, low power:  ABT           LVT

low noise, high speed:  ABT AHC       ALVC LVT LVC (ALB LV)
low noise, high drive:  ABT (F)       LVT
low noise, low power:   AHC ABT       ALVC LVT LVC (ALB LV AHC)

low power, high speed:  ABT AHC       ALVC (LVT LVC ALB)
low power, high drive:  ABT           LVT
low power, low noise:   AHC ABT       ALVC LVT LVC (ALB LV AHC)

migration:
HC  -> AHC (speed, power)
    -> LVC, AHC (3.3v)
AC  -> AHC (noise)
    -> ABT (drive, speed)
    -> LVC, ALVC (3.3v)
F   -> ABT (speed)
    -> LVC, LVT (3.3v)
BCT -> ABT (speed)
    -> LVT (3.3v)
ABT -> LVT, ALVC (3.3v)

GTL, GTL-P

output open-drain CMOS, 25-ohm(typ) pullup
input differential, reference to R-2R voltage divider between Vcc/GND (2/3 Vcc)
GTL uses 1.2V
GTL+ and GTLP use 1.5V

for multislot parallel backplanes
GTLP - open-drain, 100MHz
VME - push-pull, 40Mbit/s with legacy termination

GTLP - 3.3v, 5v-tolerant, Ioff, supports precharge, live insertion



bus switches

simple FET switch that's open bidirectional (fraction of ohms to tens of ohms) or closed (high-Z)
replacement for standard bus switches (HC244, HC245...) when bus driving/buffering not needed
low propagation delay (0.25ns)
low resistance (5..10ohm)
low capacitance (8..12pF on-state, 3..5pF off-state)
fast throughput (100-500 MHz)
no drive current

switch:       one-to-one
mux/demux:    one-to-one-from-several
bus exchange: switch matrix

CBT - general purpose 5v

NMOS N-FET
Vcc 4..5.5v

CBTD has a level-shifting diode
CBTR has a series damping resistor

CBT-C - improved 5v

active undershoot clamping down to -2V (undervoltage on one side won't glitch other side)
Ioff for partial-off
faster switching, lower Ron, better ESD compared to CBT

CBTLV - 3.3v, 2.5v

N-FET and P-FET in parallel
Vcc 2.3..3.6v
rail-to-rail IO, no voltage clamping

CB3Q - 3.3v, 2.5v, to 500MHz

FET with gate charge pump
  - gate charge pump for low and flat Ron (<10 ohm)
rail-to-rail IO to 5.0v
can switch fast signals up to 500 MHz

CB3T - 5/3.3v bus translator

mixed signal operations (2.5/3.3/5v)
either side tolerant to 5v
passing signal clamped to chip's Vcc
Vcc 2.3..3.6v

naming

CB - Cross Bar
74CB(1|2|3)(|T|Q|1G)XXX(|2)XXXX(|C)
(1|2|3) - Vcc 1.8v, 2.5v, 3.3v
(|T|Q|1G) - T=translator, Q=gate charge pump, 1G=single-gate
(|2) - nothing or series damping resistor
(|C) - nothing or -2V undershoot protection

analog switches

AUC - advanced ultralow voltage CMOS   - 0.8..2.5v, 3.6v tolerant
LVC - low-voltage CMOS                 - 3v, 5v-tolerant
LV-A - low-voltage CMOS                - 2..5.5v, 5v-tolerant, Ioff, migration path from HC/HCT
HCT - high-speed CMOS, TTL-levels      - low power, noise, price
HC - high-speed CMOS                   - like HCT
CD4000 - old CMOS                      - up to 20V Vcc, wide voltage range

I2C IO expanders

            kHz  address     Vcc  5V-tol. bits/IO power int rst config
  PCA9536   400  1000-001  2.3..5.5   y    4 pp                  cfg
! PCF8574   100  0100-xxx  2.5..6.0        8 pp         int
! PCF8574A  100  0111-xxx  2.5..6.0        8 pp         int
  PCA9554/A 400  0100-xxx  2.3..5.5   y    8 pp         int      cfg
  PCA9557   400  0011-xxx  2.3..5.5   y    8 pp/OD  low     rst  cfg
  PCA6107   400  0011-xxx  2.3..5.5   y    8 pp/OD  low int rst  cfg
  PCF8575   400  0100-xxx  2.5..5.5       16 pp         int
  PCF8575C  400  0100-xxx  4.5..5.5       16    OD      int
  PCA9535   400  0100-xxx  2.3..5.5   y   16 pp     low int      cfg
  PCA9539   400  1110-1xx  2.3..5.5   y   16 pp     low int rst  cfg
  PCA9555   400  0100-xxx  2.3..5.5   y   16 pp         int      cfg
  PCA9534

pp=push-pull, OD=open-drain
cfg=has config register
low=low power
rst=has reset
int=has interrupt

I2C level converter

PCA9306
from 1.2 1.5 1.8 2.5 3.3 volts (low-volt side) to 2.5 3.3 5 volts (high-volt side, must be higher than low-volt)
SCL/SDA pins at high impedance when EN=low

I2C multiplexers

            kHz  address     Vcc  5V-tol.  bits/IO   int rst
  PCA8550   400  1001-110  3.0..3.6        5bit pp
  PCA9544A  400  1110-xxx  2.3..5.5   y    4ch  OD   int
  PCA9545A  400  1110-xxx  2.3..5.5   y    4ch  OD   int rst
  PCA9546A  400  1110-xxx  2.3..5.5   y    4ch  OD       rst
  PCA9548A  400  1110-xxx  2.3..5.5   y    4ch  OD       rst




If you have any comments or questions about the topic, please let me know here:
Your name:
Your email:
Spambait
Leave this empty!
Only spambots enter stuff here.
Feedback: